1. Field of the Invention
The present invention relates to video surveillance and monitoring systems, and more particularly, to video surveillance and monitoring systems that stores video image data in an off-site storage site.
2. Discussion of the Related Art
Surveillance and monitoring systems have played a valuable role in many contexts. For example, surveillance video cameras are well renowned for capturing images of criminals that have burglarized various financial and commercial institutions. Video cameras have also played an increasingly valuable role in less visible contexts. For example, video cameras are increasingly being used to monitor work environments to ensure productivity or compliance with operating procedures. Additionally, video cameras are also valuable in providing evidence that establishes the non-occurrence of events in insurance fraud cases.
Video surveillance and monitoring systems will continue to proliferate as new applications of the video technology are identified. Limitations of conventional video surveillance and monitoring systems, however, greatly reduce the ultimate effectiveness of the technology.
FIG. 1 illustrates a conventional video surveillance and monitoring environment 100. Video surveillance and monitoring environment 100 includes a client site 110 and a viewing site 120. Client site 110 is a self-contained operation that governs the capture and storage of analog video image data. In a typical installation, client site 110 consists of a video camera 114 coupled to a video cassette recorder (VCR) 112. Analog video data captured by video camera 114 is stored onto a videotape 130 that has been inserted into a VCR 112.
As one can readily appreciate, conventional surveillance and monitoring environment 100 is subject to severe limitations. First, client site 110 is a highly insecure environment. Access to the sole copy of the captured image data is limited only by the relative security procedures that control the access to the location where videotapes 130 are stored. For example, in a criminal context, a perpetrator need only access the location in client site 110 that houses VCR 112. Once accessed, videotape 130 can be located and ultimately removed from the premises, thereby removing the sole piece of evidence.
Even assuming that videotape 130 has not been removed from client site 110, the video surveillance operation is severely limited. The ultimate goal of the surveillance process is to provide images to a particular party that is responsible or interested in the events occurring at client site 110. That individual is often located in a remote location relative to client site 110. If that remote location, illustrated as viewing site 120, is separated by a significant geographical distance, then videotape 130 needs to be shipped through insecure channels (e.g., express mail) to the interested party. Even if the videotape 130 is hand-delivered, videotape 130 may not reach the hands of the interested party residing in viewing site 120 for up to 3 days. This substantial delay is often unacceptable in situations that require a swift or timely response by the responsible organization.
In addition to the security and responsiveness issues described above, video surveillance and monitoring environment 100 also suffers from inherent technical limitations. Videotape image storage is limited by the physical capacity of videotape 130. This limited capacity creates numerous problems in situations that require continual surveillance.
Human factors are therefore necessary to cope with the physical limitations of surveillance and monitoring environment 100. The entry of human factors creates another set of operational problems. VCRs 112 may not be reloaded. Recorded videotapes 130 can also be misplaced, mislabeled, or cataloged in error. These errors are particularly problematic because the archival nature of video surveillance and monitoring environment 100 would be severely impacted.
Advances in computer technology have augmented the functionality of conventional video surveillance systems. In particular, analog video image systems have been replaced by digital video image systems. An example of this updated video surveillance and monitoring environment is illustrated in FIG. 2.
Video surveillance and monitoring environment 206 includes client site 210 and viewing site 220. In a typical installation, client site 210 consists of a video camera 214 coupled to a server computer 212. Video images captured by video camera 214 are stored on an electronic storage medium (e.g., hard drive, tape drive, etc.) coupled to server computer 212. Video images stored on server computer 212 are accessible by user workstation 222 at viewing site 220 via a direct dial-up connection.
The ability to retrieve images via a direct dial-up connection significantly improves the timeliness of delivery of image data to an interested party. However, video surveillance and monitoring environment 200 is still subject to significant limitations. In particular, the functionality at client site 210 is impacted by significant maintenance issues.
First, the ongoing system maintenance of customized and proprietary software resident on server computer 212 impacts overall system availability. This is particularly problematic when considering the multiplicative effect introduced by a client""s needs at multiple client sites 210. Each individual server computer 212 would require a separate software upgrade whenever a software patch or new version becomes available. In a similar manner, software resident on each user workstation 222 may also require frequent software updates.
Maintenance issues are also relevant to the actual system operation of server computer 212. Although the capacity of electronic storage devices (not shown) coupled to server computer 212 is much larger relative to the storage capacity of videotapes 130, a technician must routinely get involved in the coordination of the overall video image archive. For example, the technician must monitor the relative fullness of the storage device that is in active use to ensure that memory is not being overrun. Further, a technician must ensure that removable storage devices are not misplaced, mislabeled, or cataloged in error.
In general, the existence of a physical library of removable storage devices leads to a highly insecure environment. In a similar fashion to video surveillance and monitoring environment 100, access to the sole copy of the archived video image data is limited only by the relative security that controls the physical access to the library of removable storage devices. The removal of a removable storage device from client site 210 is an inherent fault of video surveillance and monitoring environment 200.
The security issues surrounding dial-up access to stored video image data is also significant. Remote users operating at client workstation 222 are typically given access to data stored at client site 210 based upon a simple check of a user ID and corresponding password. This level of access security is minimal and, in many cases, is entirely inappropriate for maintaining sufficient privacy of stored video image data.
More generally, access to video image data stored at client site 210 is also limited by the communications capacity of server computer 212. In many instances, server computer 212 is configured with only a single communication port (not shown). This single communication port limits the remote access to only a single user at a time. In these cases, multiple, simultaneous remote user access would not be possible, thereby limiting the overall utility of video surveillance and monitoring environment 200. It should also be noted that access to server computer 212 via a dial-up connection would also be subject to any applicable long distance or ISDN charges.
As thus described, video surveillance and monitoring environments 100, 200 each have significant limitations that affect one or more characteristics of system reliability, system security, and system performance. What is needed therefore is a video surveillance and monitoring environment that addresses each of these concerns while providing virtually unlimited and instantaneous remote access to video image data.
The present invention provides a framework for real-time off-site video image storage that enables increased functionality in the retrieval of video images. An off-site storage site is coupled to camera servers at client sites via a private network. Each camera server is further coupled to one or more surveillance cameras.
Video images captured by cameras located at the client sites are forwarded to an off-site server via a camera server. Video images received by the off-site server are produced for live viewing and/or archived in an image database.
Users can retrieve live or archived video images through a client workstation that communicates with the off-site server over the public Internet. Retrieval of video images is based on a web-browser interface. Archived video images can be viewed through VCR-type controls that control the playback of cached video images. Live viewing of video images is supplemented by real-time camera control functions that alter the pan-tilt-zoom (PTZ) position of the camera producing the live images. Commands for controlling the PTZ camera are encoded by the client workstation and transmitted to the off-site server. The off-site server, operating as a proxy between the client workstations and the camera servers, converts the camera control codes into binary-coded camera control command strings that are recognizable by the particular camera.